Use class modifiers to detect primitive classes

Author: dmlloyd

java.base/src/main/java/java/lang/Class$_native.java

@@ -74,10 +74,6 @@ public boolean isArray() {
         return dims.intValue() > 0 || CompilerIntrinsics.isPrimArray(typeId);
     }
 
-    public boolean isPrimitive() {
-        return CompilerIntrinsics.isPrimitive(CompilerIntrinsics.getTypeIdFromClass((Class<?>)(Object)this));
-    }
-
     public Class<? super T> getSuperclass() {
         type_id typeId = CompilerIntrinsics.getTypeIdFromClass((Class<?>)(Object)this);
         if (CompilerIntrinsics.isJavaLangObject(typeId) || CompilerIntrinsics.isPrimitive(typeId) || CompilerIntrinsics.isInterface(typeId)) {

java.base/src/main/java/java/lang/Class$_patch.java

@@ -230,6 +230,11 @@ public Class<?> getNestHost() {
         return nestHost;
     }
 
+    @Replace
+    public boolean isPrimitive() {
+        return (modifiers & (1 << 17)) != 0;
+    }
+
     // todo: @Replace public Class<?> arrayType() { ... }
     // todo: @Replace public Class<?> componentType() { ... }
     // todo: @Remove private final Class<?> componentType;